Monster Cookies Are Chewy, Chocolatey, and Peanut Buttery

Packed with chocolate chips and M&Ms, these cookies are naturally gluten-free.

By
Kalisa Marie Martin
Kalisa Marie Martin
Kalisa Marie Martin
Kalisa Marie Martin a is classically trained chef, content creator, and travel entrepreneur of Jamaican heritage.
Learn about Simply Recipes' Editorial Process
Updated December 29, 2023
Kalisa Marie Martin
Close-up: monster cookies on a cooling rack with a bowl of M&M's, and on the counter next to the rack, a monster cookie, and a bowl of chocolate chips with a few on the counter

Simply Recipes / Mihaela Kozaric Sebrek

Monster cookies are soft-baked, peanut butter-based cookies loaded up with oats, chocolate chips, and M&Ms. They’re crisp on the outside and soft and chewy on the inside. This version is flourless, relying on peanut butter and oats to create an irresistible texture.

These are famously kid-pleasers, but who are we kidding—monster cookies are a combination of everyone’s favorite things. 

What Oats to Use for Monster Cookies

This recipe requires quick-cooking oats. Because the cookies are flourless, the finer texture of quick-cooking oats is critical for binding everything together. If you only have old-fashioned oats on hand, pulse them a few times in a food processor to break them down so they resemble the quick-cooking variety.

A Note on Nut Butter

Creamy peanut butter is the classic base for monster cookies. While chunky will work too, it adds a significant crunch to each bite. If you’re avoiding peanuts for an allergy, or just want to try something new, almond butter makes a delicious swap. Note that the cookies made with almond butter will be flatter, but will still have their signature chewy middles.

In any case, be sure your nut butter is completely emulsified. Natural nut butters, made of just nuts and salt with the oil separated, are not recommended. Look for no-stir creamy nut butter instead. Need it to be entirely nut-free? Go for sunflower seed butter.  

Close-up: monster cookies on a cooling rack with a bowl of M&M's, and on the counter next to the rack, a monster cookie, a bowl of chocolate chips, some rogue M&M's on the counter, and a baby blue kitchen towel

Simply Recipes / Mihaela Kozaric Sebrek

Mixing Up the Mix-Ins

It’s not a monster cookie without M&Ms and chocolate chips, but you can always put your own twist on it! There are countless flavors of M&Ms to try, plus other candies like Reese's Pieces, Heath Bar bits, and more. 

The chocolate chips can be semi-sweet like we’re using here, or they can be milk or dark chocolate depending on how sweet you’d like your cookies. Chopped nuts, like pecans, would be a great addition, or toss in some raisins for a bit of chew. 

Naturally Gluten-Free

While oats do not contain gluten, they may come in contact with grains that do during their production and processing. If you want to ensure these cookies are completely gluten-free, be sure to use oats that are labeled as gluten-free. All of the other ingredients called for are naturally gluten-free.

Monster cookies on the counter with one cookie bitten into and a small bowl of M&M's

Simply Recipes / Mihaela Kozaric Sebrek

How to Store and Freeze Monster Cookies

Store baked monster cookies in an airtight container at room temperature and they will stay fresh for 3 to 5 days. To freeze, place completely cooled cookies in an airtight container or freezer bag and they’ll keep in the freezer for up to 2 months. When ready to enjoy them, thaw them at room temperature or heat them in the microwave for about 30 seconds. 

Raw cookie dough can be stored in the fridge for up to 3 days before baking and up to 2 months in the freezer. To freeze, portion the dough into balls, top with the M&Ms and chocolate chips, and freeze them in a single layer. Then, transfer them to an airtight container or freezer bag. When ready to bake, do so from frozen and simply add a couple of minutes to the baking time.

Another Way to Make Monster Cookies

Pressed for time? Try our super-easy monster cookie bars recipe!

A plateful of monster cookies with chocolate chips and M&Ms on the side, and a hand reaching in to grab one

Simply Recipes / Mihaela Kozarić Šebrek

Peanut Butter Treats

Monster Cookies

Prep Time 15 mins
Cook Time 14 mins
Total Time 29 mins
Servings 22 to 24 servings
Yield 22 to 24 cookies

Ingredients

  • 1 cup (255g) creamy peanut butter

  • 1/4 cup unsalted butter, room temperature 

  • 1/2 cup (100g) packed light brown sugar 

  • 1/2 cup (100g) granulated sugar

  • 2 large eggs, room temperature

  • 2 teaspoons vanilla extract

  • 1 teaspoon baking soda

  • 1/2 teaspoon kosher salt

  • 3 cups (260g) quick-cooking oats

  • 1 cup M&Ms

  • 1 cup semi-sweet chocolate chips

Method

  1. Preheat the oven to 350°F. 

    Line two baking sheets with parchment paper or silicone baking mats.

    Two baking trays lined with parchment paper for monster cookie recipe

    Simply Recipes / Mihaela Kozaric Sebrek
  2. Cream the peanut butter, butter, and sugars:

    In a large bowl or stand mixer, cream together the peanut butter, butter, brown sugar, and granulated sugar on medium speed for 2 minutes, scraping down the sides halfway through.

    Butter, brown and white sugar, and peanut butter in a bowl for monster cookie recipe

    Simply Recipes / Mihaela Kozaric Sebrek
    Ingredients creamed together in a bowl for monster cookie recipe

    Simply Recipes / Mihaela Kozaric Sebrek
  3. Add the eggs and vanilla:

    Stop the mixer and add both eggs and the vanilla. Beat for 2 minutes on medium speed. It will look like a thick paste.

    Vanilla extract and eggs added to bowl with other wet ingredients for monster cookie recipe

    Simply Recipes / Mihaela Kozaric Sebrek
    Bowl of wet ingredients after whisked together for monster cookie recipe

    Simply Recipes / Mihaela Kozaric Sebrek
  4. Add the dry ingredients and mix-ins:

    Stop the mixer and scrape down the sides. Add the baking soda and salt and beat for 30 seconds more.

    Add the oats and mix on low speed until fully combined.

    Reserve 2 tablespoons each of the M&Ms and chocolate chips and add the remainder to the oat mixture. Stir by hand with a spatula and combine thoroughly. 

    Simple Tip!

    It can be tricky to get all of the mix-ins to incorporate into the dough. The good news is these are gluten-free, so you don’t have to worry so much about over-working the dough. Just keep mixing and poke any straggling chocolate and candies into the dough balls before baking.

    Monster cookie batter in a bowl (without mix-ins)

    Simply Recipes / Mihaela Kozaric Sebrek
    M&M's and chocolate chip cookies added to the bowl of monster cookie dough, and next to it, two small bowls (one with chocolate chip, one with M&M's)

    Simply Recipes / Mihaela Kozaric Sebrek
    Bowl of monster cookie dough with mix-ins next to two small bowls with more mix-ins (one with chocolate chips, another with M&M's)

    Simply Recipes / Mihaela Kozaric Sebrek
  5. Scoop and bake:

    Use a heaping medium cookie scoop or spoon to portion the dough into 1 1/2-inch balls (for a total of 22 or so balls) and place them at least 2 inches apart on the prepared baking sheets. Then, using your hands, roll them into uniform balls and press the reserved M&Ms and chocolate chips onto the tops of each cookie dough ball.

    Bake until the edges are just starting to turn golden brown, 12 to 16 minutes, rotating the pans halfway.

    Dollops of monster cookie dough added to a parchment paper lined baking sheet using a cookie scoop, and in the surroundings, the bowl with more monster cookie dough and two small bowls with more mix-ins (one with chocolate chips, the other with M&M's)

    Simply Recipes / Mihaela Kozaric Sebrek
  6. Cool and serve:

    Let cookies rest on the baking sheet for 5 minutes before using a spatula to transfer them to a wire rack to cool. Serve warm or at room temperature.

    Once the cookies have cooled completely, store them in an airtight container for 3 to 5 days. They can also be frozen for up to 2 months.

    Love the recipe? Leave us stars and a comment below!

    Baked monster cookies on the parchment paper lined baking sheet

    Simply Recipes / Mihaela Kozaric Sebrek
    Plateful of monster cookies with some on the counter (a cookie with a bite missing also on the counter) next to a bowl of chocolate chips and a bowl of M&M's

    Simply Recipes / Mihaela Kozaric Sebrek
Nutrition Facts (per serving)
208 Calories
11g Fat
24g Carbs
5g Protein
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Nutrition Facts
Servings: 22 to 24
Amount per serving
Calories 208
% Daily Value*
Total Fat 11g 15%
Saturated Fat 4g 19%
Cholesterol 21mg 7%
Sodium 151mg 7%
Total Carbohydrate 24g 9%
Dietary Fiber 2g 8%
Total Sugars 13g
Protein 5g
Vitamin C 1mg 3%
Calcium 21mg 2%
Iron 1mg 6%
Potassium 170mg 4%
*The % Daily Value (DV) tells you how much a nutrient in a food serving contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.
Nutrition information is calculated using an ingredient database and should be considered an estimate. In cases where multiple ingredient alternatives are given, the first listed is calculated for nutrition. Garnishes and optional ingredients are not included.